Effects of organic selenium on growth, muscle composition, and antioxidant system in rainbow trout

This experiment was conducted to understand the effects of organic selenium on rainbow trout, Oncorhynchus mykiss. Fish (33.47±0.15 g; n = 216) were randomly assigned to four treatment groups consisting of three replicates of 18 fish each in 100 × 100 × 125 cm cages. The fish were fed a basal diet supplemented with 2, 3, or 4 mg/kg organic Se (Sel-Plex®) supplementation for 8 weeks. Muscle of fish fed the unsupplemented control diet had a lower (p0.05) in proximate composition except for protein content in fish fed the 3 mg/kg diet. Glutathione peroxidase (GSH-Px), catalase (CAT), and superoxide dismutase (SOD) activity was significantly higher (p<0.05) and liver malondialdehyde (MDA) concentration significantly lower in fish fed the supplemented diets than in the control. Results show that 3 mg/kg Se supplementation is most effective for growth and hepatic antioxidant enzyme activity in rainbow trout